Ignore interval checks for climatology time axes, and fix interval checks being ingored for time1 axes

[mauzey1]

Resolves #943

These changes will allow CMOR to write datasets for climatology variables, specifically for variables that have the "Diurnal Mean" time axis time3. It will allow them by ignoring the time interval check since the diurnal mean time axes will have irregular intervals.

This pull request will also fix a bug where the interval check for time1 axes are ignored when they are not defined with bounds values using cmor_axis.

[taylor13]

Looks good (but I didn't check the "test" code). Will we now bypass the check on interval for all climatology axes, or only the time3 axis? Either way is o.k., but I'd like to know.

thanks,
Karl

[mauzey1]

@taylor13 Using cmor_write to pass time values for climatology variables, not just those with time3, will now skip the time interval check just like when passing time values to cmor_axis.

[taylor13]

Great! Thanks.